#!/bin/bash

# Tetris Game


#APP declaration
APP_NAME="${0##*[\\/]}"
APP_VERSION="1.0"


#颜色定义
cRed=1
cGreen=2
cYellow=3
cBlue=4
cFuchsia=5
cCyan=6
cWhite=7
colorTable=($cRed $cGreen $cYellow $cBlue $cFuchsia $cCyan $cWhite)

#位置和大小
iLeft=3
iTop=2
((iTrayLeft = iLeft + 2))
((iTrayTop = iTop + 1))
((iTrayWidth = 10))
((iTrayHeight = 15))

#颜色设置
cBorder=$cGreen
cScore=$cFuchsia
cScoreValue=$cCyan

#控制信号
#该游戏使用两个进程，一个用于接收输入，一个用于游戏流程和显示界面;
#当前者接收到上下左右等按键时，通过向后者发送signal的方式通知后者。
sigRotate=25
sigLeft=26
sigRight=27
sigDown=28
sigAllDown=29
sigExit=30

#七种不同的方块的定义
#通过旋转，每种方块显示的样式可能有几种
box0=(0 0 0 1 1 0 1 1)
box1=(0 2 1 2 2 2 3 2 1 0 1 1 1 2 1 3)
box2=(0 0 0 1 1 1 1 2 0 1 1 0 1 1 2 0)
box3=(0 1 0 2 1 0 1 1 0 0 1 0 1 1 2 1)
box4=(0 1 0 2 1 1 2 1 1 0 1 1 1 2 2 2 0 1 1 1 2 0 2 1 0 0 1 0 1 1 1 2)
box5=(0 1 1 1 2 1 2 2 1 0 1 1 1 2 2 0 0 0 0 1 1 1 2 1 0 2 1 0 1 1 1 2)
box6=(0 1 1 1 1 2 2 1 1 0 1 1 1 2 2 1 0 1 1 0 1 1 2 1 0 1 1 0 1 1 1 2)
#所有其中方块的定义都放到box变量中
box=(${box0[@]} ${box1[@]} ${box2[@]} ${box3[@]} ${box4[@]} ${box5[@]} ${box6[@]})
#各种方块旋转后可能的样式数目
countBox=(1 2 2 2 4 4 4)
#各种方块在box数组中的偏移
offsetBox=(0 1 3 5 7 11 15)

#每提高一个速度级需要积累的分数
iScoreEachLevel=50        #be greater than 7

#运行时数据
sig=0                #接收到的signal
iScore=0        #总分
iLevel=0        #速度级
boxNew=()        #新下落的方块的位置定义
cBoxNew=0        #新下落的方块的颜色
iBoxNewType=0        #新下落的方块的种类
iBoxNewRotate=0        #新下落的方块的旋转角度
boxCur=()        #当前方块的位置定义
cBoxCur=0        #当前方块的颜色
iBoxCurType=0        #当前方块的种类
iBoxCurRotate=0        #当前方块的旋转角度
boxCurX=-1        #当前方块的x坐标位置
boxCurY=-1        #当前方块的y坐标位置
iMap=()                #背景方块图表

#初始化所有背景方块为-1, 表示没有方块
for ((i = 0; i < iTrayHeight * iTrayWidth; i++)); do iMap[$i]=-1; done


#接收输入的进程的主函数
function RunAsKeyReceiver()
{
    local pidDisplayer key aKey sig cESC sTTY

    pidDisplayer=$1
    aKey=(0 0 0)

    cESC=`echo -ne "\033"`
    cSpace=`echo -ne "\040"`

    #保存终端属性。在read -s读取终端键时，终端的属性会被暂时改变。
    #如果在read -s时程序被不幸杀掉，可能会导致终端混乱，
    #需要在程序退出时恢复终端属性。
    sTTY=`stty -g`

    #捕捉退出信号
    trap "MyExit;" INT TERM
    trap "MyExitNoSub;" $sigExit

    #隐藏光标
    echo -ne "\033[?25l"


    while :
    do
        #读取输入。注-s不回显，-n读到一个字符立即返回
        read -s -n 1 key

        aKey[0]=${aKey[1]}
        aKey[1]=${aKey[2]}
        aKey[2]=$key
        sig=0

        #判断输入了何种键
        if [[ $key == $cESC && ${aKey[1]} == $cESC ]]
        then
            #ESC键
            MyExit
        elif [[ ${aKey[0]} == $cESC && ${aKey[1]} == "[" ]]
        then
            if [[ $key == "A" ]]; then sig=$sigRotate        #<向上键>
            elif [[ $key == "B" ]]; then sig=$sigDown        #<向下键>
            elif [[ $key == "D" ]]; then sig=$sigLeft        #<向左键>
            elif [[ $key == "C" ]]; then sig=$sigRight        #<向右键>
            fi
        elif [[ $key == "W" || $key == "w" ]]; then sig=$sigRotate        #W, w
        elif [[ $key == "S" || $key == "s" ]]; then sig=$sigDown        #S, s
        elif [[ $key == "A" || $key == "a" ]]; then sig=$sigLeft        #A, a
        elif [[ $key == "D" || $key == "d" ]]; then sig=$sigRight        #D, d
        elif [[ "[$key]" == "[]" ]]; then sig=$sigAllDown        #空格键
        elif [[ $key == "Q" || $key == "q" ]]                        #Q, q
        then
            MyExit
        fi

        if [[ $sig != 0 ]]
        then
            #向另一进程发送消息
            kill -$sig $pidDisplayer
        fi
    done
}

#退出前的恢复
function MyExitNoSub()
{
    local y

    #恢复终端属性
    stty $sTTY
    ((y = iTop + iTrayHeight + 4))

    #显示光标
    echo -e "\033[?25h\033[${y};0H"
    exit
}


function MyExit()
{
    #通知显示进程需要退出
    kill -$sigExit $pidDisplayer

    MyExitNoSub
}


#处理显示和游戏流程的主函数
function RunAsDisplayer()
{
    local sigThis
    InitDraw

    #挂载各种信号的处理函数
    trap "sig=$sigRotate;" $sigRotate
    trap "sig=$sigLeft;" $sigLeft
    trap "sig=$sigRight;" $sigRight
    trap "sig=$sigDown;" $sigDown
    trap "sig=$sigAllDown;" $sigAllDown
    trap "ShowExit;" $sigExit

    while :
    do
        #根据当前的速度级iLevel不同，设定相应的循环的次数
        for ((i = 0; i < 21 - iLevel; i++))
        do
            sleep 0.02
            sigThis=$sig
            sig=0

            #根据sig变量判断是否接受到相应的信号
            if ((sigThis == sigRotate)); then BoxRotate;        #旋转
            elif ((sigThis == sigLeft)); then BoxLeft;        #左移一列
            elif ((sigThis == sigRight)); then BoxRight;        #右移一列
            elif ((sigThis == sigDown)); then BoxDown;        #下落一行
            elif ((sigThis == sigAllDown)); then BoxAllDown;        #下落到底
            fi
        done
        #kill -$sigDown $$
        BoxDown        #下落一行
    done
}


#BoxMove(y, x), 测试是否可以把移动中的方块移到(x, y)的位置, 返回0则可以, 1不可以
function BoxMove()
{
    local j i x y xTest yTest
    yTest=$1
    xTest=$2
    for ((j = 0; j < 8; j += 2))
    do
        ((i = j + 1))
        ((y = ${boxCur[$j]} + yTest))
        ((x = ${boxCur[$i]} + xTest))
        if (( y < 0 || y >= iTrayHeight || x < 0 || x >= iTrayWidth))
        then
            #撞到墙壁了
            return 1
        fi
        if ((${iMap[y * iTrayWidth + x]} != -1 ))
        then
            #撞到其他已经存在的方块了
            return 1
        fi
    done
    return 0;
}


#将当前移动中的方块放到背景方块中去,
#并计算新的分数和速度级。(即一次方块落到底部)
function Box2Map()
{
    local j i x y xp yp line

    #将当前移动中的方块放到背景方块中去
    for ((j = 0; j < 8; j += 2))
    do
        ((i = j + 1))
        ((y = ${boxCur[$j]} + boxCurY))
        ((x = ${boxCur[$i]} + boxCurX))
        ((i = y * iTrayWidth + x))
        iMap[$i]=$cBoxCur
    done

    #消去可被消去的行
    line=0
    for ((j = 0; j < iTrayWidth * iTrayHeight; j += iTrayWidth))
    do
        for ((i = j + iTrayWidth - 1; i >= j; i--))
        do
            if ((${iMap[$i]} == -1)); then break; fi
        done
        if ((i >= j)); then continue; fi

        ((line++))
        for ((i = j - 1; i >= 0; i--))
        do
            ((x = i + iTrayWidth))
            iMap[$x]=${iMap[$i]}
        done
        for ((i = 0; i < iTrayWidth; i++))
        do
            iMap[$i]=-1
        done
    done

    if ((line == 0)); then return; fi

    #根据消去的行数line计算分数和速度级
    ((x = iLeft + iTrayWidth * 2 + 7))
    ((y = iTop + 11))
    ((iScore += line * 2 - 1))
    #显示新的分数
    echo -ne "\033[1m\033[3${cScoreValue}m\033[${y};${x}H${iScore}         "
    if ((iScore % iScoreEachLevel < line * 2 - 1))
    then
        if ((iLevel < 20))
        then
            ((iLevel++))
            ((y = iTop + 14))
            #显示新的速度级
            echo -ne "\033[3${cScoreValue}m\033[${y};${x}H${iLevel}        "
        fi
    fi
    echo -ne "\033[0m"


    #重新显示背景方块
    for ((y = 0; y < iTrayHeight; y++))
    do
        ((yp = y + iTrayTop + 1))
        ((xp = iTrayLeft + 1))
        ((i = y * iTrayWidth))
        echo -ne "\033[${yp};${xp}H"
        for ((x = 0; x < iTrayWidth; x++))
        do
            ((j = i + x))
            if ((${iMap[$j]} == -1))
            then
                echo -ne "  "
            else
                echo -ne "\033[1m\033[7m\033[3${iMap[$j]}m\033[4${iMap[$j]}m[]\033[0m"
            fi
        done
    done
}


#下落一行
function BoxDown()
{
    local y s
    ((y = boxCurY + 1))        #新的y坐标
    if BoxMove $y $boxCurX        #测试是否可以下落一行
    then
        s="`DrawCurBox 0`"        #将旧的方块抹去
        ((boxCurY = y))
        s="$s`DrawCurBox 1`"        #显示新的下落后方块
        echo -ne $s
    else
        #走到这儿, 如果不能下落了
        Box2Map                #将当前移动中的方块贴到背景方块中
        RandomBox        #产生新的方块
    fi
}

#左移一列
function BoxLeft()
{
    local x s
    ((x = boxCurX - 1))
    if BoxMove $boxCurY $x
    then
        s=`DrawCurBox 0`
        ((boxCurX = x))
        s=$s`DrawCurBox 1`
        echo -ne $s
    fi
}

#右移一列
function BoxRight()
{
    local x s
    ((x = boxCurX + 1))
    if BoxMove $boxCurY $x
    then
        s=`DrawCurBox 0`
        ((boxCurX = x))
        s=$s`DrawCurBox 1`
        echo -ne $s
    fi
}


#下落到底
function BoxAllDown()
{
    local k j i x y iDown s
    iDown=$iTrayHeight

    #计算一共需要下落多少行
    for ((j = 0; j < 8; j += 2))
    do
        ((i = j + 1))
        ((y = ${boxCur[$j]} + boxCurY))
        ((x = ${boxCur[$i]} + boxCurX))
        for ((k = y + 1; k < iTrayHeight; k++))
        do
            ((i = k * iTrayWidth + x))
            if (( ${iMap[$i]} != -1)); then break; fi
        done
        ((k -= y + 1))
        if (( $iDown > $k )); then iDown=$k; fi
    done

    s=`DrawCurBox 0`        #将旧的方块抹去
    ((boxCurY += iDown))
    s=$s`DrawCurBox 1`        #显示新的下落后的方块
    echo -ne $s
    Box2Map                #将当前移动中的方块贴到背景方块中
    RandomBox        #产生新的方块
}


#旋转方块
function BoxRotate()
{
    local iCount iTestRotate boxTest j i s
    iCount=${countBox[$iBoxCurType]}        #当前的方块经旋转可以产生的样式的数目

    #计算旋转后的新的样式
    ((iTestRotate = iBoxCurRotate + 1))
    if ((iTestRotate >= iCount))
    then
        ((iTestRotate = 0))
    fi

    #更新到新的样式, 保存老的样式(但不显示)
    for ((j = 0, i = (${offsetBox[$iBoxCurType]} + $iTestRotate) * 8; j < 8; j++, i++))
    do
        boxTest[$j]=${boxCur[$j]}
        boxCur[$j]=${box[$i]}
    done

    if BoxMove $boxCurY $boxCurX        #测试旋转后是否有空间放的下
    then
        #抹去旧的方块
        for ((j = 0; j < 8; j++))
        do
            boxCur[$j]=${boxTest[$j]}
        done
        s=`DrawCurBox 0`

        #画上新的方块
        for ((j = 0, i = (${offsetBox[$iBoxCurType]} + $iTestRotate) * 8; j < 8; j++, i++))
        do
            boxCur[$j]=${box[$i]}
        done
        s=$s`DrawCurBox 1`
        echo -ne $s
        iBoxCurRotate=$iTestRotate
    else
        #不能旋转，还是继续使用老的样式
        for ((j = 0; j < 8; j++))
        do
            boxCur[$j]=${boxTest[$j]}
        done
    fi
}


#DrawCurBox(bDraw), 绘制当前移动中的方块, bDraw为1, 画上, bDraw为0, 抹去方块。
function DrawCurBox()
{
    local i j t bDraw sBox s
    bDraw=$1

    s=""
    if (( bDraw == 0 ))
    then
        sBox="\040\040"
    else
        sBox="[]"
        s=$s"\033[1m\033[7m\033[3${cBoxCur}m\033[4${cBoxCur}m"
    fi

    for ((j = 0; j < 8; j += 2))
    do
        ((i = iTrayTop + 1 + ${boxCur[$j]} + boxCurY))
        ((t = iTrayLeft + 1 + 2 * (boxCurX + ${boxCur[$j + 1]})))
        #\033[y;xH, 光标到(x, y)处
        s=$s"\033[${i};${t}H${sBox}"
    done
    s=$s"\033[0m"
    echo -n $s
}


#更新新的方块
function RandomBox()
{
    local i j t

    #更新当前移动的方块
    iBoxCurType=${iBoxNewType}
    iBoxCurRotate=${iBoxNewRotate}
    cBoxCur=${cBoxNew}
    for ((j = 0; j < ${#boxNew[@]}; j++))
    do
        boxCur[$j]=${boxNew[$j]}
    done


    #显示当前移动的方块
    if (( ${#boxCur[@]} == 8 ))
    then
        #计算当前方块该从顶端哪一行"冒"出来
        for ((j = 0, t = 4; j < 8; j += 2))
        do
            if ((${boxCur[$j]} < t)); then t=${boxCur[$j]}; fi
        done
        ((boxCurY = -t))
        for ((j = 1, i = -4, t = 20; j < 8; j += 2))
        do
            if ((${boxCur[$j]} > i)); then i=${boxCur[$j]}; fi
            if ((${boxCur[$j]} < t)); then t=${boxCur[$j]}; fi
        done
        ((boxCurX = (iTrayWidth - 1 - i - t) / 2))

        #显示当前移动的方块
        echo -ne `DrawCurBox 1`

        #如果方块一出来就没处放，Game over!
        if ! BoxMove $boxCurY $boxCurX
        then
            kill -$sigExit ${PPID}
            ShowExit
        fi
    fi



    #清除右边预显示的方块
    for ((j = 0; j < 4; j++))
    do
        ((i = iTop + 1 + j))
        ((t = iLeft + 2 * iTrayWidth + 7))
        echo -ne "\033[${i};${t}H        "
    done

    #随机产生新的方块
    ((iBoxNewType = RANDOM % ${#offsetBox[@]}))
    ((iBoxNewRotate = RANDOM % ${countBox[$iBoxNewType]}))
    for ((j = 0, i = (${offsetBox[$iBoxNewType]} + $iBoxNewRotate) * 8; j < 8; j++, i++))
    do
        boxNew[$j]=${box[$i]};
    done

    ((cBoxNew = ${colorTable[RANDOM % ${#colorTable[@]}]}))

    #显示右边预显示的方块
    echo -ne "\033[1m\033[7m\033[3${cBoxNew}m\033[4${cBoxNew}m"
    for ((j = 0; j < 8; j += 2))
    do
        ((i = iTop + 1 + ${boxNew[$j]}))
        ((t = iLeft + 2 * iTrayWidth + 7 + 2 * ${boxNew[$j + 1]}))
        echo -ne "\033[${i};${t}H[]"
    done
    echo -ne "\033[0m"
}


#初始绘制
function InitDraw()
{
    clear
    RandomBox        #随机产生方块，这时右边预显示窗口中有方快了
    RandomBox        #再随机产生方块，右边预显示窗口中的方块被更新，原先的方块将开始下落
    local i t1 t2 t3

    #显示边框
    echo -ne "\033[1m"
    echo -ne "\033[3${cBorder}m\033[4${cBorder}m"

    ((t2 = iLeft + 1))
    ((t3 = iLeft + iTrayWidth * 2 + 3))
    for ((i = 0; i < iTrayHeight; i++))
    do
        ((t1 = i + iTop + 2))
        echo -ne "\033[${t1};${t2}H||"
        echo -ne "\033[${t1};${t3}H||"
    done

    ((t2 = iTop + iTrayHeight + 2))
    for ((i = 0; i < iTrayWidth + 2; i++))
    do
        ((t1 = i * 2 + iLeft + 1))
        echo -ne "\033[${iTrayTop};${t1}H=="
        echo -ne "\033[${t2};${t1}H=="
    done
    echo -ne "\033[0m"


    #显示"Score"和"Level"字样
    echo -ne "\033[1m"
    ((t1 = iLeft + iTrayWidth * 2 + 7))
    ((t2 = iTop + 10))
    echo -ne "\033[3${cScore}m\033[${t2};${t1}HScore"
    ((t2 = iTop + 11))
    echo -ne "\033[3${cScoreValue}m\033[${t2};${t1}H${iScore}"
    ((t2 = iTop + 13))
    echo -ne "\033[3${cScore}m\033[${t2};${t1}HLevel"
    ((t2 = iTop + 14))
    echo -ne "\033[3${cScoreValue}m\033[${t2};${t1}H${iLevel}"
    echo -ne "\033[0m"
}


#退出时显示GameOVer!
function ShowExit()
{
    local y
    ((y = iTrayHeight + iTrayTop + 3))
    echo -e "\033[${y};0HGameOver!\033[0m"
    exit
}


#显示用法.
function Usage
{
    cat << EOF
    Usage: $APP_NAME
    Start tetris game.
    -h, --help              display this help and exit
    --version           output version information and exit
EOF
}
#游戏主程序在这儿开始.
if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    Usage
elif [[ "$1" == "--version" ]]; then
    echo "$APP_NAME $APP_VERSION"
elif [[ "$1" == "--show" ]]; then
    #当发现具有参数--show时，运行显示函数
    RunAsDisplayer
else
    bash $0 --show&        #以参数--show将本程序再运行一遍
    RunAsKeyReceiver $!        #以上一行产生的进程的进程号作为参数
fi